Fixed-route transit is known. A set of fixed transit routes is established for a geographic area, and a schedule is set for each. The fixed transit routes and the schedules can be selected based on many factors, including population and ridership distribution, street route suitability and safety, employment centers, etc. Fixed route transit is typically subsidized by metropolitan, state/provincial and/or federal government. As a result, it is desirable to provide such fixed-route transit services as efficiently as possible.
Some transit organizations that provide fixed-route transit services review and modify their fixed transit routes frequently. These changes may be made in response to changes in ridership along the current routes, changing population distributions, changes in available funding, changes in the availability of vehicles and/or operators, school and university calendar changes, etc. When such transit organizations modify their fixed transit routes, they typically re-generate a transit route map by hand. The transit route map is generated by tracing each fixed transit route over a street network map. Each fixed transit route can include a number of patterns. Patterns are the paths followed by a vehicle from one end of a route to another end. The outgoing trip in one direction is generally treated as a separate pattern from the incoming trip along the other direction for a fixed transit route. Each of these two patterns has timing information for stops along the route. Further, the vehicle path may be altered during some periods of the day or on weekends. For example, a vehicle may be diverted away from a busy intersection during rush hour. A separate pattern is defined to demarcate the new path taken by the vehicle. Each pattern must be traced for a fixed transit route. The process of tracing each of the patterns of each fixed transit route for a transit network can take a significant amount of time, weeks in many cases.
Currently, computer systems exist for generating transit route maps. Such computer systems present a street map to a user to enable the user to input patterns that make up the fixed transit routes. Each pattern is inputted by a user by marking on the street map the starting and ending points of the pattern and, optionally, a number of intermediate points along the pattern. The computer system then determines a path between the points defined by the user using a street routing algorithm and a street network database. The street network database stores street network segments. Each street network segment represents a stretch of road between points at which more than one path is available (i.e., an intersection). The street routing algorithm creates projections by linking street network segments.
The street routing algorithm requires a starting point and an ending point to generate a pattern along a street network. The computer system maps the starting point and ending point for a pattern provided by a user onto a street network in order to determine these inputs for the street routing algorithm. In particular, the computer system maps the starting point and ending point inputted by the user by determining the closest street network segments to each. In the case where two or more street network segments are equidistant to the starting or ending point, one of the street network segments is selected randomly. If the selected street network segment adjacent the starting point is a one-way street, the start of the pattern generated by the street routing algorithm may travel further away from the ending point. Similarly, if the selected street network segment adjacent the ending point is a one-way street, the end of the pattern generated by the street routing algorithm may overshoot the ending point before returning to it. Even if the selected adjacent street network segment is not one-way, it may yield a less-than-desirable route.
It can be desirable to generate fixed transit routes that have expected travel times of a certain length or less in some cases. By providing service whereby vehicles are expected to depart at the same number of minutes past the hour for each hour for periods, or all, of the day, clients can more easily plan their trips using the fixed-route transit service. In such cases, there is benefit to having the expected round trip time for a vehicle to perform the fixed transit route be under an hour. If the expected travel time for a vehicle to perform the fixed transit route exceeds an hour, another vehicle and driver need to be deployed along the route to adhere to the desired schedule. Thus, by determining better paths for fixed transit routes, both equipment and personnel costs can be kept down.
It is therefore an object of the invention to provide a novel method and system for generating fixed transit routes.